| 摘要 |
<p>PURPOSE:To improve the picture quality of a transmission picture without increasing quantity of transmission by deciding a wider range in positive an negative prediction error ranges and assigning more quantization representative values to the wider prediction error range. CONSTITUTION:According to an MSB signal outputted from an MSB extraction circuit 46, a quantizer 34 selects a quantization characteristic with wider negative quantization representative range when the MSB signal is logical 1 and selects the quantization characteristic with wider positive quantization representative value range when the MSB signal is logical 0, quantizes a difference e1 to convert it into a DPCM code. An inverse quantizer 38 uses an MSB signal output of an MSB extraction circuit 46 to invert the DPCM code with the inverse quantization characteristic relating to the quantization characteristic of the quantizer 34 into a quantizing representative value. An adder 40 adds a prediction value to the quantization representative value, a limiter 42 applies amplitude limit to use it as a prediction value of the succeeding sampling value.</p> |
